He doesn't say because he isn't asked. If he asked, I'm sure he wouldn't evade the question. And I'd be an idiot to think Ron Paul's presidency will automatically solve all of our problems. Not even close. His presidential win is just a first step. It's neither the main, nor even the most important one. Just the first.
We need to elect Ron Paul like ppl in Senate, Congress, State Senates and Congresses, Governors, Attorney Generals, all the way to fucking City Hall janitors.
And you're incorrect about not being able to accomplish anything. The Drug war is run by Office of National Drug Control Policy, directly under the President. One stroke of the pen, and that Office is memory. Look at all these other offices that are directly under the president and he can do just about what he wants to with them and doesn't have to answer to Congress.
http://en.wikipedia.org/wiki/Cabinet_of_the_United_States
There are plenty of ways to be effectual.